5.  The applicants were born in 1946 and 1938 respectively and live in Kazichene.
6.  On 27 May 1998 their son, Mr Rosen Stoyanov, born in 1967, a parachute instructor in the Bulgarian Army, died when performing a parachute jump from a Mi-17 helicopter during a training exercise of the Ministry of the Interior's Special Anti-Terrorism Squad.
7.  Six paratroopers were scheduled to jump on that day. Before getting into the helicopter they were examined by a doctor who confirmed that they were physically fit. The helicopter took off at 1 p.m. and several minutes later reached a height of about 1,100 metres. Immediately before the start of the parachute jumps Chief Sergeant T., in charge of the jumps, instructed the helicopter's pilots to speed up. The pilots responded “You have it”. It is unclear what the exact speed thus reached was, because, as it was established later, the helicopter's device recording the parameters of the flight had not been loaded with a tape.
8.  One of the paratroopers, Mr G., jumped first. Immediately after the jump, his body was thrust back by the air stream and his head passed about 20 centimetres from the left rear tyre of the helicopter.
9.  The applicants' son jumped four seconds later. Immediately after the jump, his head hit the left rear tyre of the helicopter and he became unconscious. His body fell freely and hit the ground.
10.  Four seconds later the next paratrooper, Mr V., jumped. His head also hit the left rear tyre of the helicopter and he became unconscious. Sixty to seventy metres from the ground he regained consciousness and attempted unsuccessfully to open his parachute. His body also hit the ground.
11.  After the accidents with the applicants' son and Mr V. the parachute jumps stopped and the helicopter landed. The two bodies were located soon afterwards.
12.  On 27 May 1998 the Ministers of the Interior and Defence appointed a ten-member commission to investigate the reasons that had led to the fatal accident. The commission, which included paratroopers, doctors and other experts, conducted inspections, interviewed witnesses and examined documents. On 6 June 1998 it presented an interim report proposing, with a view to establishing properly the circumstances of the accident, that an experiment with a dummy being thrown from a helicopter at different speeds be carried out and that the helicopter's manufacturer be asked for additional technical information. However, it appears that none of these actions was taken.
13.  On 24 June 1998 the commission submitted its final report. It established that after Chief Sergeant T. had instructed the crew to speed up (see paragraph 7 above), the helicopter had increased its speed from about 150 to about 200 km/h. This estimation was based on ground control data.
14.  Furthermore, the commission established that the helicopter, which was built in 1986, had been in a good state of technical repair, and that its equipment had been functioning well during the fatal flight. The three members of the crew were experienced and qualified. The commission established that up to 27 May 1998 Mr Rosen Stoyanov had performed 450 parachute jumps, 112 of which were from a Mi-17 helicopter. Mr V. had performed 178 jumps, 120 of which were from a Mi-17 helicopter.
15.  The commission concluded that the accident had been caused by
“the inappropriate speed of the helicopter and the position of the paratroopers' bodies at the time of jumping, not in conformity with that speed”.
Additionally, the accident had been due to:
“1) incomplete coordination between the helicopter's crew and the paratroopers; 2) shortcomings in the preparation and conduct of the flight on the part of the helicopter's crew; and 3) shortcomings in the organisation and the conducting of the parachute jumps on the part of the Ministry of the Interior's Special Anti-Terrorism Squad.”
16.  The commission criticised the failure of the officials responsible for the organisation of the flight to load the helicopter's recording device with a tape (see paragraph 7 above), which was against the rules.
17.  Furthermore, the commission criticised Chief Sergeant T.'s failure to communicate to the crew the exact speed he needed when he requested them to speed up. Neither had the speed at which the jumps were to be performed been indicated by the officer in charge of the training (he had remained on the ground) before the helicopter took off.
18.  The commission recommended various measures for the prevention of similar accidents in the future, mostly concerning the training of paratroopers and flight preparation. It is unclear whether any of them were put into practice.
19.  On 30 June 1998 the commission's report was affirmed by the Minister of Defence, but not by the Minister of the Interior. Subsequently, the document was extended to the prosecuting authorities who investigated the deaths of Mr Stoyanov and Mr V. (see below).
20.  On 27 May 1998 the Sofia military regional prosecutor's office opened a preliminary investigation into the accident.
(a)  Initial investigative actions
21.  A post-mortem examination of the bodies of the applicants' son and Mr V. was carried out on 28 May 1998. It concluded that the death had been caused by “numerous traumas incompatible with the maintenance of life”. There were no traces of alcohol or poison in the blood.
22.  Nor were any traces of alcohol or poison found in the crew members' blood.
23.  Colonel O., the flight captain, was questioned on 28 May 1998. He stated that the helicopter had been checked and found to be in good technical repair just before the flight. Furthermore, he stated that after Chief Sergeant T. had asked the pilots to speed up he had increased speed from 130 to 150 km/h. After the first three paratroopers had jumped, he had been told to land as two of the paratroopers' parachutes had not opened.
24.  Senior Sergeant A., the flight engineer, was questioned on 1 June 1998. He also testified that the helicopter's speed at the time when the parachute jumps had started had been 150 km/h. The speed and the height had not changed during the jumps. When jumping from the helicopter, Mr G. had plunged energetically and Mr Rosen Stoyanov and Mr V. had not, which, in Senior Sergeant A.'s view, had been the reason for the fatal accident.
25.  On 29 May 1998 Mr G., who had jumped before Mr Stoyanov, testified that immediately after jumping he had felt an unexpectedly strong air stream.
26.  Chief Sergeant P., who had been on board the helicopter, was questioned on 29 May 1998. He explained that he had seen Mr G.'s head pass about 20 centimetres from the helicopter's left rear tyre and then Mr Rosen Stoyanov and Mr V. hit the tyre. Because of the force of the blow, Mr Stoyanov's body had turned several times in the air.
27.  Lieutenant D., who had also been in the helicopter, testified that he, too, had seen Mr Rosen Stoyanov's head hit the tyre. Captain C., who had also been on board, described the position of Mr G.'s body immediately after he had jumped as “totally abnormal”.
28.  Chief Sergeant T., who had been in charge of the jumps and had been scheduled to jump after Mr V., was questioned on 29 May 1998. He explained that he had not seen Mr Rosen Stoyanov and Mr V. hit the tyre but had become aware of the abnormal position of Mr V.'s body and had not jumped. He had not noticed any change in the speed, height or direction of the helicopter during the parachute jumps.
29.  During the first several weeks after 27 May 1998 the investigator in charge of the case examined other witnesses, conducted inspections and collected documentary evidence.
30.  On 28 May 1998 he appointed the members of the internal inquiry commission of the Ministries of the Interior and Defence (see paragraphs 12-19 above) as experts in the criminal proceedings, with the task of determining the cause of the two paratroopers' deaths. Since the experts failed to submit a report within the months that followed, on 25 November 1998 a prosecutor from the Sofia military regional prosecutor's office stayed the proceedings.
(b)  Subsequent developments
31.  On several occasions in 1999 and early 2000 the Sofia military regional prosecutor's office sent letters to the Ministries of the Interior and Defence requesting that their officials appointed as experts prepare and submit a report for the purposes of the criminal proceedings.
32.  On 18 April 2000 the criminal proceedings were resumed and the prosecutor in charge of the case appointed a new group of experts from the National Military University in Dolna Mitropoliya, with the task of assessing the reasons for the deaths of the applicants' son and Mr V.
33.  On 25 April 2000 the experts submitted their conclusions, specifying that the information they had been given was insufficient, there being no data on the exact parameters of the flight, and also that they were not experts in parachuting; therefore, they were not able to draw up a formal expert report.
34.  The experts considered that the helicopter's speed at the time of Mr Rosen Stoyanov's and Mr V.'s jumps had been between 150 and 170 km/h. However, in their view, the speed was not related to the fatal accident, which had instead been caused by the two paratroopers' jumping technique; this had not been in compliance with the respective instructions for performing parachute jumps.
35.  In July and October 2000 the Sofia military regional prosecutor's office sent new letters to the Ministries of the Interior and Defence requesting again that the experts appointed on 28 May 1998 (see paragraph 30 above) draw up a formal report.
36.  On 17 November 2000 the Ministry of Defence experts submitted their report. The group included four paratroopers and a doctor. The Ministry of the Interior experts did not sign the document.
37.  On the basis of ground control data, the Ministry of Defence experts established that the helicopter's speed at the time of Mr Rosen Stoyanov's and Mr V.'s jumps had been 210 km/h. The experts were of the opinion that Mr Stoyanov and Mr V. had not committed any errors when jumping from the helicopter, but pointed out that they did not possess the expertise to assess whether the helicopter's crew had committed any errors that might have led to the tragic accident. The experts noted that the two paratroopers' parachutes had been well packed and in good repair and that the weather conditions at the time had not affected the flight.
(c)  Discontinuance of the criminal proceedings
38.  On 4 February 2002 a prosecutor from the Sofia military regional prosecutor's office discontinued the criminal proceedings. Relying on witness testimony and the conclusions of the National Military University experts (see paragraph 34 above), he found that the helicopter's speed and course of flight did not change significantly during the parachute jumps and were not related to the fatal accident. He accepted that sufficient data could not be collected to assess whether the helicopter's crew had committed any errors and that the applicants' son and Mr V. had not complied with the respective instructions on performing parachute jumps.
39.  On an appeal by the applicants, on 6 August 2002 the Sofia Military Court quashed the prosecutor's decision. On 28 November 2002 the Military Court of Appeal affirmed the lower court's findings. It held that the prosecutor had breached the procedural rules and that the conclusions of the National Military University experts, on which his decision had been based, could not serve as valid evidence in the case.
40.  After the case was remitted to the prosecution, some of the witnesses were re-examined. On an unspecified date Chief Sergeant T., who had been in charge of the parachute jumps, explained that when he had instructed the helicopter crew to speed up he had meant a speed of about 150 km/h, as was usual. He had become aware later, apparently from the conclusions of the internal inquiry, that the speed had been above 200 km/h. He considered that this, coupled with a possible minor side inclination of the helicopter, which would have shifted the position of the left rear tyre vis-à-vis the paratroopers' bodies, had been the reason for the accident with the applicants' son and Mr V.
41.  On 13 May 2003 a prosecutor from the Sofia military regional prosecutor's office requested the Ministers of the Interior and Defence to nominate seven experts in aerodynamics, aviation, meteorology and parachuting to be appointed experts in the criminal proceedings and draw up a new expert report. He received no reply.
42.  On 16 June 2003 the prosecutor appointed another group of experts – a physician from the Military Medical Academy and five lecturers from the Air Transport Department of the Technical University in Sofia – with the task of assessing the reasons for the two paratroopers' deaths on 27 May 1998.
43.  The experts submitted their report on 25 July 2003. They considered it scientifically impossible for Mr Stoyanov and Mr V. to have hit the helicopter's left rear tyre; in their view those blows had been “made up”. The experts considered that the two paratroopers had wrongly estimated the distance to the ground and had failed to open their parachutes in time; this had led to their deaths. Furthermore, the paratroopers had failed to comply with the relevant instructions on the position of their bodies at the time of jumping. The speed and course of the helicopter had not been related to their death.
44.  On 10 June 2004 a prosecutor from the Sofia military regional prosecutor's office once again discontinued the criminal proceedings. In his decision, he referred to the expert report of 25 July 2003 and its conclusion that the applicants' son and Mr V. had not in fact hit the left rear tyre of the helicopter (see paragraph 43 above). However, he also mentioned the witness testimony indicating that these impacts had happened (see paragraphs 26-27 above). He failed to examine the apparent controversy between those two groups of evidence and to indicate which version he found plausible. He merely concluded, after describing the evidence collected in the case, that there was no appearance of a crime.
45.  Upon appeal by the first applicant, on 30 June 2004 the prosecutor's decision was upheld by the Sofia Military Court. Examining the evidence collected in the case, that court dismissed the conclusion of the expert report of 25 July 2003 (see paragraph 43 above) that Mr Stoyanov and Mr V. had not hit the helicopter's left rear tyre; it considered that in this regard the testimony of the other participants in the flight was reliable. Nevertheless, the domestic court accepted the experts' conclusion to the effect that Mr Stoyanov and Mr V. had not positioned themselves correctly when they jumped. It concluded that this had been the reason for their hitting the tyre and falling to the ground. Accordingly, it upheld the prosecution's conclusion that no offence had been committed in the case.
46.  Soon after their son's death, the applicants sought the compensation provided for in section 249(2) of the Armed Forces Act 1995 (see paragraph 49 below). As they had not received that sum by 2003, they brought a claim. They sought the compensation provided for in section 249(2) of the Armed Forces Act, plus interest, as provided for in section 250 (ibid.).
47.  While the proceedings were pending, the Bulgarian Army paid up the compensation due, which was in the amount of 8,316.48 Bulgarian levs (BGN), the equivalent of approximately 4,300 euros (EUR). Therefore, in a judgment of 6 July 2004 the Sofia District Court only awarded the applicants the interest accrued, in accordance with section 250 of the Armed Forces Act, which amounted to BGN 427.58, the equivalent of EUR 220. That judgment was not appealed against and entered into force.
48.  In September 2003 the applicants also sought indemnification from the company with which their son had been insured by the Bulgarian Army. They claimed a sum of about BGN 3,000, the equivalent of EUR 1,540. However, that indemnification was refused as they had failed to claim it within the statutory three-year time-limit from the date of their son's death.